Method for continuously producing glass fibre mats



Feb. 22, 1966 w. H. w. SCHULLER 3,

METHOD FOR CONTINUOUSLY PRODUCING GLASS FIBREMATS 2 Sheets-Sheet 1Original Filed May 1, 1962' lNVE/VTOR WER/VfR H. W. SCHULLER 1 6 13 11Quinn i 'l ATTORNEYS Feb. 22, 1966 w. H. w. SCHULLER 3,235,913

METHOD FOR CONTINUOUSLY PRODUCING GLASS FIBRE MATS Original Filed May 1,1962 2 Sheets-Sheet 2 //VVE/VTOR WRIVR H. W. .SCHULLER United StatesPatent 3,235,913 METHOD FOR CONTINUOUSLY PRODUCING GLASS FIBRE MATSWerner Hugo Wilhelm Schuller, Postfach 76, Wertheim (Main), GermanyOriginal application May 1, 1962, Ser. No. 191,625, now Patent No.3,187,387. Divided and this application Aug. 3, 1964, Ser. No. 392,988Claims priority, application Germany, May 6, 1961, Sch 29,673 4 Claims.(Cl. 19156.3)

This application is a divisional application of my copending applicationSerial Number 191,625 filed May 1, 1962.

The invention relates to a method and apparatus for the continuousproduction of a glass fibre mat from staple glass fibre in which thestaple fibres are carried in an air stream from a position ofmanufacture to a position of deposition on a conveyor belt on which thefibres are built-up in superposed relation to form a mat of the desireddensity and thickness.

In such a process a main difficulty is to convey the fibres separatelyin the air stream in such manner as to be laid uniformly on the conveyorbelt to present a mat of uniform predetermined density and thicknessthroughout the mat.

This is especially important for mats of a thickness of 0.3-0.8 mm.which only weigh 4275 g./m. The slightest uneven glass fibre allocationper unit area will show and produce a variation in tensile strength,density, porosity, electrical resistance or light transmissioncharacteristics When such mats are used for example, for roofing felt,pipe wrap, air filters, battery retainer mats and lampshades. All theseapplications have to rely on a uniform mat thickness.

The invention has among its objects to avoid these disadvantages, and toprovide for substantially uniform flow of the air stream carrying thestaple fibres from the position of manufacture to the position ofdeposition on the conveyor belt.

According to the method of the invention the flow of air carrying thefibres is controlled so as to maintain the fibres separate andtravelling in a path close to the top of guide means formed at one endas a stationary nozzle and at the other end formed as an invertedchannel section adapted to be horizontally reciprocated whereby thefibres in such movement may be deposited at a uniform rate and densityon an endless moving conveyor belt which is pervious to air, and beneathwhich a vacuum is constantly applied.

According to the invention, in a method of conveying staple glass fibresfrom a position of manufacture to a position of deposition onto anair-pervious conveyor belt, the guide channel is formed to an invertedopen U-section and the separate staple fibres are caused to float in anair current in a zone adjacent the top of the guide channel, and meansare provided to project additional streams of air, advantageouslydirected upwardly at an angle to the air stream in the guide channel,whereby a steady flow of fibres is passed to the reciprocatingdistributing head therefor, advantageously downwardly curved at the end,to direct the fibres in a continuous stream onto the surface of theair-pervious belt in such manner as to build up a mat made of staplefibres disposed at random on the belt to a desired thickness anddensity.

Such air stream or streams may be forced into the main stream underpressure or may be drawn into the main stream by suction.

Alternatively, or in addition, the cross-sectional area of the guidemeans may be varied for a determined length Patented Feb. 22, 1966 'iceor may be tapered with a view to maintaining a uniform rate of flow ofthe fibre-conveying air.

The invention is of particular advantage in the case of thin mats bywhich is meant mats within the range of thickness of 0.3 to 0.8 mm. andwith a weight of 42- g./m.

According to the invention furthermore, units consisting offibre-producing and fibre-conveying means may be provided in pluralityalong each side of the conveyor belt advantageously in staggeredrelation and if desired at an angle to the main axis of the conveyorbelt and partitions may be provided between each unit.

According to the invention furthermore, means may be provided forcontrolling and varying the speed of reciprocation of the distributingheads of the units and/or of the belt where such is necessitated for anyreason, for example, when recharging one of the fibre-producing units,whereby the weight and thickness of the mat will remain substantiallyuniform throughout.

According to the invention furthermore, the guide means for the airstream carrying the fibres may be formed with an intermediatereciprocable duct between the stationary nozzle member and thedistributing head and adapted to move in synchronism with thereciprocating head.

The invention further comprises the features of construction hereinafterdescribed.

The invention is diagrammatically illustrated by way of example in theaccompanying drawings, in which:

FIGURE 1 is a diagrammatic cross-section on a reduced scale of asimplified embodiment of the invention;

FIGURE 2 is a cross-section on a reduced scale of an installation forthe production of a fibre mat, with units set up alongside a conveyorbelt in accordance with the invention;

FIGURE 3 is a still further schematized complete View on a still furtherreduced scale according to FIGURE 2;

FIGURE 4 is a depositing diagram of an individual depositing head for afibre mat deposited according to the invention, and

FIGURES 5 to 7 show a modified construction of apparatus according tothe invention, in front view and in three different phases of movement.

While any known method may be used for the production of staple fibresand a current of air generated in any convenient manner for conveyingthe fibres from a position of manufacture to a position of deposition onthe convey-or belt, in the accompanying drawings and followingdescription the method of forming the fibres has been describedaccording to my United States Patent No. 2,996,102, issued August 15,1961, in which the air generated by a drawing drum is used in part atleast to convey the fibres from the position of manufacture to theposition of deposition on the belt.

The air carrying the staple fibres moves in the direction of the arrow A(FIGURE 1) into a stationary deflection member or nozzle 4 whichreverses the direction of flow and carries the fibers through the nozzlein close proximity to the top wall 7 thereof. The nozzle member isformed with a bottom wall 8 and side walls 9 forming a closed guide ductwhich tapers towards this outlet.

The bottom wall 8 of the nozzle is inclined upwardly at an angle towardsthe outlet. Thus air is caused to flow along the inner surface of thewall 7, and at an inclination to the vertical as indicated by the arrowB, with the result that the fibres are caused to closely hug the innerwall of the duct.

Cooperating with the stationary nozzle member 4 is a reciprocatingmember 13 formed of inverted U-section and with a horizontal portionoverlapping the nozzle outlet in its reciprocation and with the otherouter end of said member downwardly directed. Means are provided toreciprocate the guide means transversely across the conveyor belt 5 ashereinafter described.

In operation the staple fibres produced by the drawing drum are carriedalong in the direction of the arrow C to be deposited in a reciprocatingmovement on the air pervious belt 5. Suction is applied on the undersideof the belt.

The high speed of drum 2 causes a peripheral air flow which serves toconvey the individual fibres to their depositing means.

The circulating wind produced by the drum and guided by the nozzleproduces a force component, approximately as indicated by arrow A, whilethe nozzle-type design of the fibre guide duct according to the presentinvention produces a component as indicated by arrow B.

It will be understood that the distributing head is completely opentoward the bottom and that only three sides, that is, the cover wall 14and the two side walls act as restrictions. The flowing fibres do notfall under gravity but are carried along the cover wall 14 until theyare deposited at 15, thus enabling the fibres to be conveyed in ambienttemperature conditions without need for complicated fixtures.

As shown in FIGURES 2 and 3 apparatus according to the invention may beprovided in number, for example, ten, set up along one or both sides ofthe conveyor belt 5. The belt 5 is air-permeable and consists, forexample, of wire netting. Suction boxes 16 are provided in spacedrelationship underneath the belt, each of which boxes is provided with amotor 17 driving a suction fan 18. The conveyor belt 5 passes overrollers 19 and is driven by a belt'drive or gear drive 20 and anelectric motor 21.

- FIGURES 2 and 3 also show the reciprocating heads 13 in variousoperating positions. Each fibre-producing and conveying unit may bedisposed at an angle to the conveyor belt.

The reciprocating heads are moved across the conveyor belt by means of asuitable mechanism, which does not form part of the invention.

, In FIGURE 2 the drive is a chain drive, consisting of a slottedguideway 22 mounted on the cover plate of the reciprocating head, with acarrier rod 24 on a chain 23 sliding in the guide slot, so that in thecourse of one rotation of the chain the rod makes one up and down motionand the reciprocating head is moved back and forth once. The individualchains co-operating with the reciprocating heads may be driven through acentral shaft 25, sprocket wheels 26 and chains 27.

FIGURE 4 shows the depositing path followed by one reciprocating head;the conveyor belt is designated by reference numeral 5 and the width ofa reciprocating head is illustrated at b. At each forward run (arrow E)and return run (arrow F) one reciprocating head deposits one strip offibre mat which, except for the reciprocating head of the first unit, isdeposited across or transversely of the strip deposited by the previoushead. It will be seen that in order to obtain the deposit of a fullstrip of fibre on the conveyor belt for each run of a reciprocating headthereacross, the maximum conveyor belt speed must be equal to thedistance b divided by the time required for each run of thereciprocating head across the width of the belt.

FIGURES 5 to 7 show a modified apparatus which is particularly suitablefor manufacturing wide mats, for example two meters in width and wider.For this purpose the fibre duct is subdivided into substantially uniformsections, of which the one lying closer to the fibreproducing means andgenerally indicated by the reference 28 is stationary, and the otherduct, located in the direction of movement of the reciprocating head 13,and generally designated by the reference 29, is mobile, and moves insynchronism with the reciprocating head. In doing so, the mobile section29 slides during its reciprocating motion over section 28, and thereciprocating head 13 at first over section 29 and then over thestationary section 28.

Since in this case the air flow is exposed twice to a force which isdirected, at an angle in the upward direction, it can be guided over arelatively long distance at a uniform rate of flow without disturbingthe flow of the fibres. This will ensure that the fibres will alwaysleave the distributing heads at a uniform speed and will be depositedcontinuously and uniformly on the conveyor belt.

The drive of the reciprocating head 13 and the moving section 29 of thefibre guide duct may be selected as desired, provided the movablesection is moved with a given delay or time lag in relation to thereciprocating head.

FIGURES 5 to 7 show diagrammatically a possible driving means. Similarto the embodiment according to FIGURE 2 an electric motor drives a chaindrive 32 over a pinion 31, with a rotating carrier rod 24 attached tochain drive 32. Also similar to FIGURE 2, carrier rod 24 is operativelyconnected to head 13 through slotted guideway 22 mounted on the coverplate of the reciprocating head. Head 13 is additionally connected at33a with reciprocating chain 33, which drives chain 36 over gear wheels34, 35, chain 36 being connected at 36a with the moving portion 29 ofthe fibre guide duct. As shown in FIGURES 57, chain 33 passes over gearwheel 34 and chain 36 passes over gear wheel 35, both gears 34, 35 beingmounted on a common shaft. In operation, an electric motor (not shown)drives chain 32 which imparts up and down motion to carrier rod 24which, in turn, imparts horizontal reciprocatory movement to head 13.Movement of head 13 drives chain 33 which turns gear wheels 34, 35 andsprockets 42, 49 thereby driving chain 36. However, since gear 35 has asmaller diameter than gear 34, chain 36 will be displaced aproportionately shorter distance than chain 33. Accordingly, thisarrangement provides intermediate section 29 with a delayedreciprocating movement in relation to reciprocating head 13. 1

By subdividing the fibre guide duct into a stationary section and into amoving section, which telescopes in and outwith the telescoping headduring a reciprocating movement, the distance L between the inner end ofthe conveyor belt and the drum centre can be practically reduced to thelength of thereciprocating head, which is a considerable advantage.

FIGURE 5 shows the respective, completely extended guide means 13-2928,with the reciprocating head located at a reversing position.

FIGURE 6 shows a center position and FIGURE 7 the completely closed ortelescoped position wherein the reciprocating head is located at theother reversing position.

Where a number of units are mounted in staggered relation on each sideof the conveyor belt, partition members 37 may be provided betweenadjacent units, so that any air currents which might occur particularlyat the reversing position of the distributing head, are prevented fromdisturbing the uniform and steady flow of the fibres.

If very large widths of mat are required, or if for any other reason theair flow produced by the drum is insufiicient to carry the fibers at aconstant rate of flow, additional air, as shown in FIGURE 5, may beblown-in by means of a fan, not shown, through a socket 38 into the mainair flow, in order to make up for the reduction of air pressure when thedistributing head as shown in FIG- URES, is at the outer limit of itstravel. To prevent excess air at the inner limit of travel of thereciprocating head, socket 38 is suitably provided with a throttle flap39, which is controlled by the reciprocating movement of the head 13 orby the moving section 29 of the fibre guide duct in such manner that itwill open when the telescoping system 13-29-28 opens, and will closewhen the system telescopes again.

The production of fibres does not necessarily require the use of a fastrotating drum. The air flow required may be produced with a fan orblower operating to replace the air lost in the conveyance of the fibresto the reciprocating depositing head.

FIGURE 3 shows at 40 a drying oven, in which the mat is brought to atemperature between 100 C. and 150 C. for removing any excess solvent ofthe binding agent which may be present. Following this operation the matcan be wound up immediately or can be guided through a curing chamber41, in which it is heated to a higher temperature, for example, between180 and 220 C. to set the binder.

In one example of carrying out the invention, the mat may be provided inany desired width or it may be of the standard width required inparticular industries as, for example, three feet for the roofingindustry and for use as pipe wrappings; four feet for roofing shinglesand in the building industry in general. Small widths as, for example,for battery separators, of from two inches to twelve inches or twentyinches or more or less may be produced from a standard width sheet, cuton a rerolling machine in a well-known operation.

The thickness or density of the mat may also be varied by varying thefibre thickness (or density). For example, if an individual fibre has adiameter of 12 microns (1 micron equals V1000 mm.), to obtain a mat ofan average thickness of .4 mm. requires approximately 33 layers ofindividual fibres, and will weigh approximately 46 to 48 g./m.

If the individual fibre diameter is to be increased to 14 microns, asfor example, for battery separators, the fibre diameters are increasedby about 15% as compared with the 12 micron fibre. To obtain a mat ofthe same weight as when 12 micron fibres are used, it will be apparentthat only approximately 29 layers of the 14 micron fibers are required.

The fibre diameter is determined by the speed of the rotating drawingdrum which may rotate at 2700 m./min. According to the speed of the rodfeed, the fibres thus drawn may be varied in thickness. Thus the fibrediameter is controlled by the rate of feed of moving glass rods whilemaintaining the drawing speed constant.

The surface air current created by the rotation of the drawing drum forconveying the fibres may be increased so as to convey the fibres anyadditional distance that may be required, and as hereinbefore described,additional currents of air may be projected into the main stream toensure that the fibres are conveyed the whole distance from the positionof manufacture to the position of deposition on the conveyor belt in themanner hereinbefore described.

I claim:

1. A method of manufacturing a mat of generally uniform density andthickness from staple glass fibres comprising the steps of: formingindividual staple fibres from glass filaments; entraining said fibers tofloat individually in a main current of air; travelling said maincurrent of air along and adjacent the upper periphery of an associatedguide means; controlling the rate of flow of said main air current bydirecting streams of air upwardly at an angle thereto and alsointermittently introducing additional streams of air into said main aircurrent; and directing said main air current and additional streams ofair to a deposit station at which said individual fibers are depositedin random superposed relationship to build up a mat of uniform densityand thickness.

2. A method of manufacturing a mat of generally uniform density andthickness from staple glass fibres comprising the steps of: formingindividual staple fibres from glass filaments; entraining said fibres tofloat individually in a main current of air; travelling said maincurrent of air along and adjacent the upper periphery of an associtaedreciprocating guide means; controlling the rate of fiow of said main aircurrent by directing streams of air upwardly at an angle thereto andalso introducing additional streams of air into said main air current insynchronism with the reciprocating movement of said guide means; anddirecting said main air current and additional streams of air to adeposit station at which said individual fibres are deposited in randomsuperposed relationship to build up a mat of uniform density andthickness.

3. A method of manufacturing a mat of generally unlform density andthickness from staple glass fibres comprising the steps of: formingindividual staple fibres from glass filaments; entraining said fibres tofloat individually in a main current of air; travelling said maincurrent of air along and adjacent the upper periphery of an associatedreciprocating telescoping guide means; controlling the rate of flow ofsaid main air current by directing streams of air upwardly at an anglethereto and also introducing additional streams of air into said mainair current in synchr nism with the reciprocating movement of saidtelescoping guide means; and directing said main air current andadditional streams of air to a deposit station at which said individualfibres are deposited in random superposed relationship to build up a matof uniform density and thickness.

4. The method as claimed in claim 3, including reciprocating said guidemeans between an open position and a closed position and introducingsaid additional streams of air into said main air current when saidguide means is in the open position.

References Cited by the Examiner UNITED STATES PATENTS 1,946,784 2/1934Elliott 19-1564 2,110,280 3/1938 VieWeg l9156.4 2,244,544 6/1941 Smith19-156.4 2,996,102 8/1961 Schuller 19-156.3 X 3,037,248 6/1962 Callaghan19156.4 3,051,998 9/1962 Rust et al l9l56.4

DONALD w. PARKER, Primary Examiner.

1. A METHOD OF MANUFACTURING A MAT OF GENERALLY UNIFORM DENSITY ANDTHICKNESS FROM STAPLE GLASS FIBRES COMPRISING THE STEPS OF: FORMINGINDIVIDUAL STAPLE FIBRES FROM GLASS FILAMENTS; ENTRAINING SAID FIBERS TOTHAT INDIVIDUALLY IN A MAIN CURRENT OF AIR; TRAVELING SAID MAIN CURRENTOF AIR ALONG AND ADJACENT THE UPPER PERIPHERY OF AN ASSOCIATED GUIDEMEANS; CONTROLLING THE RATE OF FLOW OF SAID MAIN AIR CURRENT BYDIRECTING STREAMS OF AIR UPWARDLY AT AN ANGLE THERETO AND ALSOINTERMITTENTLY INTRODUCING ADDITIONAL STREAMS OF AIR ONTO SAID MAIN AIRCURRENT; AND DIRECTING SAID MAIN AIR CURRENT AND ADDITIONAL STREAM OFAIR TO A DEPOSIT STATION AT WHCIH SAID INDIVIDUAL FIBERS ARE DEPOSITEDIN RANDOM SUPERPOSED RELATIONSHIP TO BUILD UP A MAT OF UNIFORM DENSITYAND THICKNESS.